Apparatus for treating a liquid with a gas



May 18, 1954 KAUNSKE 2,678,913

APPARATUS FOR TREATING A LIQUID WITH A GAS Filed Feb. 23, 1952 2 Sheets-Sheet 2 F 'ur-e J figure-4- v l I II T? 1 i; n T 1 {.51 E9 124 y a l 12 I II II I l25- 14-2 14-! 1287.- I

156 BY W Patented May 18, 1954 UNITED STATES t TENT OFFICE APPARATUS FOR TREATING A LIQUID WITH A GAS Anton A. Kalinske, Tucson, Ariz., assignor to Infilco Incorporated, Tucson, Ariz., a corporation of Delaware 8 Claims. 1

This invention relates to apparatus for treating a liquid with a gas and in particular to apparatus of this general type wherein there is maintained a circulation of liquid from a submerged gas dissemination zone, wherein the gas is dispersed or diffused through the liquid, to the liquid surface and back to the gas dissemination zone. In such apparatus it is important that the quantity of liquid circulated can be maintained substantially constant.

It is, therefore, an object of the invention to provide in an apparatus of this general type improved means for maintaining the circulation constant.

Another object is to provide an apparatus of this general type wherein th liquid circulation is independent of the quantity of gas used in the treatment.

Another object is to provide an apparatus of this type which needs a minimum of adjustment to varying conditions.

Other objects will become apparent upon consideration of the following detailed description and of the claims.

It is usual in apparatus of the type mentioned to utilize the lifting force of the gas bubbles rising through the liquid to maintain the circulation, and this is satisfactory where the treatment efiected in the apparatus requires fairly constantly the addition of gas in amounts sulficient to produce this air lift action. However, where the quantity of gas necessary for the treatment drops periodically, at regular or irregular intervals, below the amount needed for gas lift action, difficulties arise in maintaining the circulation constant by means of gas lift.

Similarly, difliculties occur when the quantity of gas used in the treatment is considerably larger than th amount needed for the gas lift supported circulation. Thus, in the biological treatment of waste waters, such as sewage, frequent changes in the quantity and quality of the waste water occur, which necessitate corresponding changes in the quantity of air supplied for the treatment. Low night flows, for example, require a correspondingly small volume of air, which may well be below that needed to maintain the desired circulation. It has, therefore, been suggested to supplement the air lift at such times by a mechanical lifting force, such as by providing an impeller in the air lift tube or passageway leading from the gas dispersion zone or chamber to the liquid surface. Such an impeller, however, usually pumps constant volumes of liquid and is not adjustable to supplement a M widely varying air lift force to provide a uniform composite lifting force for the liquid circulation. Variable capacity rotor impellers, on the other hand, would require a measure or service not usually available in waste treating plants.

To overcome these diiiiculties and provide for a constant circulation of liquid despite varying amounts of gas entering for treatment, I suggest to effect the circulation entirely by mechanical means and to provide simple means preventing any substantial effect of the gases on the circulation and encouraging their escape without disturbance in any part of the path through which the liquid is circulated.

The invention will be more readily understood by reference to the drawings wherein:

Figure 1 is a vertical sectional view of an apparatus for treating a liquid with a gas employing the invention, the section being taken along line 1-! of Figure 2;

Figure 2 is a partial horizontal sectional view along lines 2-2 of Figure 1;

Figure 3 is a horizontal sectional view of an embodiment of the invention as applied to a square tank; and

Figure l is a vertical sectional view of another type of apparatus for treating a liquid with a gas employing the invention.

In Figures 1 and 2 the invention is shown for purposes of cxemplification as applied to an apparatus of the type disclosed in my co-pending application, Serial No. 85,102. Such an apparatus comprises a tank is, provided with a launder ll into which treated clarified liquid overflows and from which it is withdrawn through an eiiluent conduit l2. A solids concentrator I3 is provided in the tank l0, and solids settled therein are withdrawn through a solids outlet conduit Hi. The tank It can be drained through a valved drain I5.

A partition structure 2!] is axially aligned in th tank it and includes a hood 2|, forming a mixing or gas dispersion chamber 22 in the lower portion of the tank It, a cylindrical partition 23 leading from the hood upwardly, and an outer tube 24 surrounding at least the upper part of the cylindrical partition 23. A radial flow rotordisperser 3G is rotatably mounted on a shaft 3| in the mixing and dispersing chamber 22. The shaft 3! is rotated by any suitable motor-reducer 32.

The inlet conduits 33 and 3 1 for liquid to be treated and for the gas used in the treatment, respectively, discharge into the gas dispersion chamber 22, preferably underneath the gas disperser 66. In such an apparatus the circulation from the mixing chamber to the liquid surface and back to the mixing chamber is usually effected by gas lift, and the mixture of liquid, solids and gas leaving the mixing chamber 22 rises through the tube 23 and overflows therefrom into the outer tube 24 to return downwardly to the mixing chamber 22. In the present improved apparatus this gas lift action is prevented, and the circulation is effected mechanically. I provide a tubular partition 46 within the cylindrical partition 23, as shown. The inner tube extends irom an elevation above the normal liquid level in the tank In, downwardly into the upper portion of the gas dispersion chamber 22, and has a bottom 4| with a central aperture or port 42. A pumping member 43 is mounted at a suitable elevation within the inner tube 46, preferably on the same shaft 3| as the disperser 30, and pumps liquid upwardly through the port 42 and the inner tube 46. The cylindrical partition 23 also is extended to an elevation above the normal liquid level. A plurality of ports and 46 are provided in the inner tube ii] and the tubular partition 23, respectively. The ports 45 and 46 can be formed as notches in the upper rims of the tubes 40 and 23, which are cut down to an elevation subjacent the normal liquid level, as shown in Figure 1. The ports also may be Windowli'ke openings in the tubes 40 and 23, as shown in Figure 4. Each pair of ports 45 and 46 is connected by a trough 41-, whose bottom 46 is located subjacent the normal liquid level and Whose side Walls 49 extend upwardly to an elevation above the normal liquid level. The troughs 41 bridge the space between the inner tube 46 and the cylindrical partition 23 and provide overflow means from the upfiow passageway Within the inner tube 42 to the 'downfiow passageway 5| between the cylindrical partition 23 and the outer tube 24.

With this construction the liquid-s'ol-ids mixture is circulated from the gas dispersion chamber '22 through the 'upflow passageway 50, across the launders or troughs 41, through the downflow passageway 5| and back into the gas dispersion chamber 22 through the lower open end of the hood 2 I. From the liquid'issuing from thedownflow passageway 5'1 a throughputportion of'clarifled liquid separates "and flows upwardly to the r "launder I I. The solids left behind by the clarified liquid are returned to the gas dispersion chamber 22 with the balance of liquid-solids mixture returning thereto.

The greatest part or the bubbles 'of undis'solved gas rises through the gas escape space 52 between the inner tube 46 and the cylindrical partition 23 and escapes to 'the atmosphere without influencing the circulation or disturbing the "separation of clarified liquid. Though the mixture of liquid "and solids pumped by the pump '43 will contain some small gas bubbles, these will not materially affect the pumping action and circulation. The speedof -thecircul'ation'can be controlled by varying the position 'of the pumping member 43 vertically'on the shaft 3i. Another mode of control therefor is the use of gates for the ports 45 to restrictthe flow therethroughand into the troughs 41, as shown for on port in Figure 4 atI 55.

The embodiment of Figure 3 illustrates the invention-as applied to a, liquid treating apparatus of the same typea's that of-Figure '1,-but arranged in a-jsquare tank. In this case the partitions 23a, "24a and 40a all are square instead of tubular. 75 'tom of theclarification chamber I2! is scraped Otherwise, the structure is the same as that of Figures 1 and 2. Again, troughs 41a, two on each side of the partitions 46a and 23a, form overflow means from the upflow passageway 50a to the downflow passageway 5Ia, bridging the gas escape space 52a.

The liquid treatin apparatus of Figure 4 is or the type disclosed in my copending application, Serial No. 131,615, for treating a liquid with a gas. In such an apparatus the liquid to be treated and gas for the treatment are also dispersed mechanically through the contents of a gas dispersion zone in the lower central part of the apparatus, and a predetermined quantity of liquid-solids mixture is circulated from the gas dispersion zone to the liquid surface and back to the dispersion zone. However, While in the apparatus of Figures 1 and 2 clarification is obtained by dynamic separation of clear liquid from a flowin stream of liquid-solids mixture, in the embodiment of Figure 4 clarification is efiected by sedimentation in a quiescent clarification zone, and the liquid-solids mixture returning from the clarification zone to the gas dispersion zone is a partially sedimented and thickened sludge.

The partition structure I26 in this embodiment includes a wall I2I rising from the iloor of the tank IIU, a trusts-conical partition I23 extending from an elevation above the upper end of the wall I2I to an elevation above the normal liquid level in tank HE! and an outer tube I24. A horizontal bafiie I25 divides the space between the upper end of wall I2I and the lower end of outer tube I24 into an outflow port I26 leading from the downflow passageway I5I into the clarification chamber I21 and an inlet port I28 leading from th clarification chamber into the gas dispersion chamber I22. A vertical baffle I29 deflects the liquid flowin through inlet port I28 downwardly.

In this structure I provide an inner partition I40, which extends from an elevation spaced above the rotor-disperser I38 to an elevation above the normal liquid level in tank IIIJ. As in Figures 1 and 2 the inner partition has an apertured bottom I4l, and a pumping member I43 is provided to pump liquid upwardly through the port I42 and the upflow passageway I50 within the inner partition I49. The troughs I4! connect ports I45 in the inner partition I40 with ports 146 in the irusto-conioal partition I23 and form overflow means from the upfiow passageway I59 to the downfiow passageway I5I across the gas escape space I52. While the ports I45 and I46 are'shown as window-like'openings, they may be in the form of notches, like the ports 45 and 46ofFigure 1.

The liquid leaving the downfiow passageway I5 I flows out into the clarification zone I21 A portion of partially thickened sludge enters th gas'dispersion chamber 122 through the inletport I28 and is deflected downwardly by the baffle I29 to the lower "por- 'tionof the chamber I22,'where it is picked up by the suction flow or thedisp'erser and mixed with newly incoming liquid and gas entering through conduits I33 and I34, respectively, and

dispersed through the liquid-solids contents of the chamber I22. Thevelocity o'f thecirculation 'can be controlled by proper positioning of the pumping member 443 vertically on shaft I3-I, or 'byproviding the ports 45 withsuitable gatesfshch 'as'the gate I55. The sludge settled-on th'e botby a conventiona1 scraper assembly I56 into a sump I51, from which it is removed through a solids outlet conduit I58.

It will be seen that my invention, whether applied to the type of apparatus exemplified in Figures 1, 2 and 3, or to the type illustrated in Figure 4, eliminates the difficulties in maintaining a constant volume of circulation which are frequently experienced in such apparatus when the circulation is based on gas lift action. At the same time, the undissolved gas bubbles can escape without causing any disturbance in any part of the apparatus. The invention is not limited to use in the particular apparatus shown in the drawings and described in the specification for purposes of exemplification and illustration. Apparatus in which the invention can be utilized with advantage can take a variety of forms. Thus, it is immaterial as far as the present invention is concerned whether the gas is disseminated through the liquid by mechanical means, as shown in the figures for purposes of illustration, or through gas difiusers or the like, the important thing being that the gas is prevented from affecting the circulation and that mechanical means are rovided which maintain a constant volume of circulation. Where the treatment requires a reasonably constant supply of gas which is adequate for the volume of circulation desired, or where gas is expressly introduced for the purpose of circulation rather than for treatment of the liquid, it is, of course, entirely satisfactory to use as lift circulation. However, where the treatment requires changing quantities of gas, my invention provides simple and efficient means to overcome the deficiencies inherent in gas lift circulation under such circumstances.

I claim:

1. An apparatus of the type described including a tank having an overflow from its upper portion and solids outlet means from a lower portion, partition means forming a gas dissemination chamber in a lower portion of said tank, an upfiow passageway leading upwardly from an upper portion of said gas dissemination chamber, and a downflow passageway leading from an elevation above said overflow downwardly, characterized by a gas escape passageway intermediate said upflow and downfiow passageways and leading from the upper portion of said gas dissemination chamber to an elevation above said overflow, an apertured plate at the lower end of said upfiow passageway, a pumpin member mounted to pump a predetermined quantity of liquid upwardly through the apertured portion of said plate, and trough means across said gas escape passageway and establishing an overflow from said upflow passageway to said downflow passageway.

2. In an apparatus for treating a liquid with a gas including a tank having an overflow from its upper portion and solids outlet means from a lower portion, wall means forming a gas dissemination chamber in the lower portion of said tank, inlet means into said gas dissemination chamber from the lower portion of said tank, a first partition extending upwardly from said wall means to an elevation above said overflow, a second partition extending about said first partition from an elevation above said overflow downwardly and being open to said tank with its lower end, the combination with said first and second partitions of a third partition laterally spaced from, and in the space within, said first partition and extending upwardly from an upper portion of said gas dissemination chamber, whereby there are formed an upflow passageway within said third partition, a downfiow passageway between said second and first partitions, and a gas escape passageway between said first and third partitions, said third partition having an apertured bottom, a pumping member mounted to pump liquid upwardly through the aperture of said bottom, and trough means extending across said gas escape passageway and connecting said upfiow passageway with said downfiow passageway, said trough means having side walls extending from adjacent but below the elevation of said overflow to above said elevation.

3. In an apparatus for treating a liquid with a gas includin a tank having an overflow from its upper portion and solids outlet means from a lower ortion, wall means forming a gas dissemination chamber in the lower portion of said tank, inlet means into said gas dissemination chamber from the lower portion of said tank, a first partition extending upwardly from said wall means to an elevation above said overflow, a second partition extending about said first partition from an elevation above said overflow downwardly and being open to said tank with its lower end, an inner partition laterally spaced from, and in the space within, said first partition and extending upwardly from an upper portion of said gas dissemination chamber, said inner partition having an apertured bottom, a pumping member in the space within said inner partition and mounted to pump a predetermined quantity of liquid through the aperture in the bottom, open ended trough means extending from said inner partition to said first partition at an elevation adjacent but below said overflow, and ports in said inner and first partitions registering with said trough means, said trough means having side walls extending to an elevation above said overflow.

4. The apparatus of claim 3 wherein said ports are in the form of notches in the upper rims of said inner and first partitions.

5. The apparatus of claim 3 wherein said ports are window-like openings in said inner and first partitions.

6. In an apparatus for treating a liquid with gas including a tank having outlet means establishing a normal liquid level therein, a gas dissemination chamber in the lower portion of the tank, wall means extending from the upper portion of said gas dissemination chamber to an upper portion of said tank, second wall means extending from the top of said tank downwardly and forming with said first wall means a downflow passageway, the combination with said first wall means of a partition laterally spaced from said first wall means and having a bottom in the upper portion of said gas dissemination chamber and extending upwardly from said bottom to an elevation above said normal liquid level, said bottom having an apertured portion, said partition forming with said first wall means an unobstructed passageway from said dissemination chamber to the top of said tank through which gases can escape freely, and forming within said partition an upfiow passageway substantially obstructed for the free passage of gases, a pumping member mounted to pump liquid from said gas dissemination chamber through said apertured portion, and means connecting said upflow passageway with said downfiow passageway, said means comprising trough means extending from said partition to said first wall means subjacent said normal liquid level, the side walls of said trough means extending to an elevation above said normal liquid level, and ports in said partition and said first wall means registering with said trough means.

7. In an apparatus for treating a liquid with gas including a tank having outlet means establishing a normal liquid level therein, a gas dissemination chamber in the lower portion of the tank, wall means extending from the upper portion of said gas dissemination chamber to an upper portion of said tank, second wall means extending from the top of said tank downwardly and forming with said first wall means a downfiow passageway, the combination with said first wall means of a partition laterally spaced from said first wall means and having a bottom in the upper portion of said gas dissemination chamber and extending upwardly from said bottom to an elevation above said normal liquid level, said partition forming with said first wall means an unobstructed passageway from said dissemination chamber to the top or said tank, said bottom having an apertured portion, a pumping member mounted to pump a predetermined quantity of liquid from said gas dissemination chamber through said apertured portion, the upper rims of said partition and said first wall means each having a plurality of symmetrically arranged notches extending to an elevation below said normal liquid level and forming registering pairs, and an open ended trough mounted across each pair of notches and bridging the space between said partition and said first wall means, said troughs having side walls extending to an elevation above said normal liquid level.

8. In an apparatus for treating a liquid with gas and clarifying the liquid wherein means are provided for disseminating entering liquid to be treated and gas through a gas dissemination chamber in the lower portion of a tank and for maintaining a circulation of liquid leading from the gas dissemination chamber to the top of the tank and back to said chamber, from which circulation clarified liquid separates and is withdrawn through clarified liquid outlet means, means for maintaining said circulation constant despite variations in the quantity of gas entering for treatment, and for providing escape of undissolved gases without disturbance in any part of the tank, said means comprising three vertical coaxial partitions extending from the top portion of said tank downwardly, the innermost of said partitions extending into the upper portion of said dissemination chamber and having a bottom with a central aperture therein, the second partition extending to the top of said chamber and providing with said innermost partition an unobstructed passageway from said chamber to the top of said tank, the third partition being in open communication at its lower end with the tank outside said chamber, ports in said innermost and said second partition at an elevation subjacent the elevation of said clarifled liquid outlet means, trough means connecting said ports and bridging said unobstructed passageway and providing an overflow from the space within said innermost partition to the space between said second and third partitions, and a rotor mounted to cause an upward flow of liquid from said chamber through said aperture and through the space within said innermost partition to said trough means.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,348,125 Green May 2, 1944 2,429,315 Green Oct. 21, 1947 FOREIGN PATENTS Number Country Date 20,744 Great Britain of 1894 

1. AN APPARATUS OF THE TYPE DESCRIBED INCLUDING A TANK HAVING AN OVERFLOW FROM ITS UPPER PORTION AND SOLIDS OUTLET MEANS FROM A LOWER PORTION, PARTITION MEANS FORMING A GAS DISSEMINATION CHAMBER IN A LOWER PORTION OF SAID TANK, AN UPFLOW PASSAGEWAY LEADING UPWARDLY FROM AN UPPER PORTION OF SAID GAS DISSEMINATION CHAMBER, AND A DOWNFLOW PASSAGEWAY LEADING FROM AN ELEVATION ABOVE SAID OVERFLOW DOWNWARDLY, CHARACTERIZED BY A GAS ESCAPE PASSAGEWAY INTERMEDIATE SAID UPFLOW AND DOWNFLOW PASSAGEWAYS AND LEADING FROM THE UPPER PORTION OF SAID GAS DISSEMINATION CHAMBER TO AN ELEVATION ABOVE SAID OVERFLOW, AN APERTURED PLATE AT THE LOWER END OF SAID UPFLOW PASSAGEWAY, A PUMPING MEMBER MOUNTED TO PUMP A PREDETERMINED QUANTITY OF LIQUID UPWARDLY THROUGH THE APERTURED PORTION OF SAID PLATE, AND THROUGH MEANS ACROSS SAID GAS ESCAPE PASSAGEWAY AND ESTABLISHING AN OVERFLOW FROM SAID UPFLOW PASSAGEWAY TO SAID DOWNFLOW PASSAGEWAY. 